The Corsair Obsidian 800D is an amazing and massive case, but even in its current state, it doesn't really have enough room for a second radiator. I wanted my new build to have two separate liquid cooling loops, so I had to find a way to mount a second radiator somewhere in the case.

After pouring over pictures online, I decided that the best way to accommodate a second radiator was to remove the lower hard drive cage and make room for the rad down there. I personally only need room for 4 hard drives, so the 4 hot swap bays accommodate me perfectly, and I have no need for the lover hard drive cage. Once I received my case, I double checked my measurements and got to work on the mod.

Before we go any further it is important to note the this will affect the warranty on the case. Redbeard said; "Obviously we’d still replace things like fans that were not affected by the mod, but the fit and finish, door panels, anything that might be affected by a structural change would be unwarrantied."

I will be posting medium size pictures to this thread. If anyone would like to see any of these pictures in greater detail / larger size, head over to the following link:800D Bottom Rad Mod Photo Set

With that said and the "Disclaimer" out of the way, here we go.

Tool wise you will need a drill, and a Dremel (Rotary Tool) to accomplish this mod. I also recommend a Rivet Gun/Tool, but its not absolutely necessary.

First you need to pop off the front panel to expose the rivets in the front of the case. The six (6) rivets shown in the picture below are the first to go. I found that a 1/8" drill bit right through the middle of the rivets works perfectly to remove them.

The front and back pieces of the rivets.

There are two (2) brackets behind the lower hard drive cage that must also be removed. Luckily they just require a screwdriver.

This is where things get tricky. The last two (2) rivets that have to be removed are located towards the back of the hard drive cage. There is not much space to maneuver, so I had to use a combination of a cutting disk and grinding stone on my Dremel to remove them. With these last rivets removed, you can now pull the hard drive cage out of the case.

You will now need to replace two (2) of the rivets we previously removed. They had to go in order to get some give when pulling out the hard drive cage, but with the cage removed you need to put them back in for structural stability. If you don't have a rivet gun, small machine screws and a nut on the back would work, but you will have to figure out what size on your own.

Hard drive cage removed, and necessary rivets have been replaced. Now we move onto cutting a larger intake hole for the radiator.

I used a HardWare Labs GTX240 for my radiator. Any 120x2 fan radiator should work just fine. The idea is to have the fans mounted on top of the radiator where they would be pulling air from the bottom of the case up through the radiator and expelling it into the other cooling zones of the case.

There are many ways one could measure out the area for the intake hole and the mounting holes, but I found using an A.C. Ryan Rad Grill was the easiest. Trace out the area for the intake cut and make note of where the mounting holes need to go.

I messed up here and made the intake too large, therefore eliminating the two mounting holes on the right. Luckily it was an easy fix as you will see later in the thread.

FYI... using a rotary tool on a steel case is not an easy task. I ate through 3 cutting discs by the time I was done. But it did the job, while making a mess of the surrounding area. Be sure to wear eye protection on this step. Tiny metal shards flying at high speeds towards your eyes should be avoided.

Done with the hard stuff. Now to attach the radiator and fans. You will also note that I removed the fan that was attached to the metal separating the PSU zone from the Mothebroard zone. It will be reattached, but in a different position as will be shown later.

I placed the Rad Grill in between the case and the radiator. I also installed some 1/4" thick weather stripping material I found at the local hardware store. It is sticky on one side and makes for a gasket of sorts between the case, radiator, and fans.

Here you can see everything secured together. The gray you may notice comes from the weather stripping material. It can be spray-painted before application if you want it to be black. Since I cut the intake a bit to large near the right corners, I had to use some washers in order to properly secure the back of the radiator to the case. I also used the same material on the rails the support the PSU towards the back of the case which can be seen two pictures down.

Installed!

This picture shows that even after the mod, a large PSU like the Corsair HX1000 has plenty of room to run your cables. I will put the cable management back-plate back onto the case once I have run my tubing to the bottom radiator. The fan has also been re-attached to the metal separator in the case above the radiator.

This should give you an idea of what airflow will be like with this mod.

Well, thats it. Thanks for taking a look and feel free to shoot me a question if you get stuck somewhere.

Update - 10/03/09

I wanted to post two additional pictures that will better enhance this mod.

Here is a 140mm magnetic fan filter that goes perfectly over the new intake cut-out area. Sticks right to the steel case, and is easily cleaned and removed. I tested before and after, and there is little to no airflow restriction while using it.

If you look closely, you will see that I added a wood dowel to better support the metal divider between the PSU & Motherboard area. Cut to fit and Spray-Painted black. Click to View Larger Image

Hey MA, did you reinstall 1/8" rivets?
Also do you think there is room for another 20mm to install a Black Ice GT Xtreme 140 or Black Ice GT Stealth 140? 153mm = 6.03". I don't have my cage out yet so I couldn't get a good measurement in the front. I also found a Bitspower Custom Design 140 Grill. I have to run my MCP655 in the bottom since I paid so much for it is the reason for the 140 instead of dual. It won't get used much for now, I am like you, waiting for the 300 Series Nvidia cards to come out.
On your 350, did you look at the aftermarket Acetal tops? I am thinking I will have to use an elbow fitting out of the top if I am going to fit it in the 5.25 bay. My system is running 1/2" tubing so I need replacement top/barbs on the 350.

Sorry for all of the questions but I broke my brain yesterday researching and figuring out just what I wanted to do with a bottom Rad and mod for it. And then Wired comes up with that remote control idea and that just sent me off in all kinds of directions :p

Hey MA, did you reinstall 1/8" rivets?
Also do you think there is room for another 20mm to install a Black Ice GT Xtreme 140 or Black Ice GT Stealth ...

Yes, I used 1/8" aluminum rivets.

As far as spacing, the height of the hard drive cage area is 115mm. The GTX140 is 54mm thick so that plus a push / pull fan configuration with 25mm thick fans gives you you a total thickness of 104mm. 1cm to spare. It will be tight, but it should work. The GTS140 (Stealth) is only 30mm thick so even more room to work with, but you will sacrifice some cooling performance over the GTX140.

I didn't really look into the replacement tops for the MCP350 pumps simply because the stock ones will work fine for where I will be putting them in one of the 5.25" bays. The two pumps will be placed side by side in the back of the 5.25" bay and a fan controller will be placed in the front. Since the two barbs shoot right out the back it will be perfect for my loops. Here is a diagram that better explains what I am trying to do.

That is what I am working one, but since you have different pumps, you will have to be a bit more creative. From what you have described, it seems you almost have it figured out. Let me know if I can be of any more help.

I ordered 2 of the reservoirs you have but Frozen only ended up having one so I have to wait even longer. Hopefully my RAM will be available by then. I liked your setup a lot but I already had all of the 1/2" barbs/fittings and the MCP655 from the primochill I had ordered as well as tygon tubing so I can't really justify not using it.

My Basic plan is this:
Corsair H50 for the 920 CPU ( I wanted to see how it performs)
The Feser 360 will be for the video cards when I get them:
( Possibly running the EK black and the Vid cards on the 360)
The 140 Rad for my Ek Full Board WC block,the RAM H30, and the Physx Card.
See, I am still confusing myself even this close to the build.

Basically 3 loops total, a little overkill but I have no idea what the new vid cards will be like as far as heat production so I am trying to err on the safe side for overclocking.
On the plus side, I am getting closer to the remote control deal with some parts from a robot shop. They also had some nice roller ball type casters that look coolhttp://www.robotshop.us/pololu-ball-...etal-ball.html

I was just gonna ask you if you popped a rivet into the shelf. I removed my HD Cage and installed a fan where the HD holes were but the shelf droops a little so I was gonna ask if you had the same thing. Those brackets for the HD cage proved to be a little pain trying to wiggle them out once I unhooked them but I got em out.

I think I am going to go with the Koolance Reservoir and Pump, RP-980BK for my other loop and use the XSPC for the other simply because it has the pump installed already and I don't have room to place a pump in the 5.25 bays like you do. I actually have to put my controller in the top and use the 45 degree BP fittings to attach to my XSPC because of my top radiator and shrouds/fans.

I was just gonna ask you if you popped a rivet into the shelf. I removed my HD Cage and installed a fan where the HD holes were but the shelf droops a little so I was gonna ask if you had the same thing.

Nice job with your fan mod.

I did notice a little bit of droop, but I fixed it with a wooden dowel spray-painted black. I cut it to fit and wedged it in between the divider and the bottom of the case and now there is no movement at all.

What was the measurement of the rod. I am looking at a a different option if you don't mind sharing ;p

It was a 1/2" rod, cut to 5" long. It may be a shade under 5" depending on how much sag there is in the divider. You will have to verify for your case.

I was originally going to use a Turnbuckle that had threaded flathead bolts on both sides so I could adjust the height of the support as needed. I also spray-painted it black, but in the end, I think the wooden dowel just turned out to be a lot easier, and looked just as good if not better.

First of all I like to thank you Mr Armageddon for his wonderful pedagogic and educational mod display here in Corsair support forum. You really set the light for the future generations.

By the way Mr Armageddon, use a threaded rod (see picture below) together with a black painted pipe as a support, then use black painted Domed Cap Nut (see picture below) in Stainless Steel or brass at top and bottom of the rod. But be accurate with the measurement on the rod & pipe vs nut so you get it right in the first place. Measure the nuts dept so you see how much of the rods thread you have at the disposal without striking the ground of the nuts. It's also recommended to use washers with wider diameter to compensate for the pressure on the Obsidian 800D case.

Then I have to say that it's really nice to see all creative people using there energy's, ideas and skills in there creations. To not mention their will to share it with others. Keep up the good work my friends!

Best regards to you all, WOLF.

Last edited by WOLF; 03-09-2010 at 09:50 AM.
Reason: Still old and unmindful.

Thanks for the writeup Wolf, Mr A did a great job and I took some of my mods directly from his. I have not been able to overclock mine to his extent but I tend to run some high graphic demand games and I run 2 to 3 instances of it so on warm days I tend to hit the 55 C Temp and my warnings start popping off even with both coolers running.
My XPSC cover came off too so I have to find something to put it back on and I have the mods for my BRay drive to become stealth when I find the time to mess with them. Once the new NVIDIA graphics cards some out I will likely redo my loops and maybe even run another Koolance reservoir/pump combo. The case is absolutely gorgeous and houses anything I can cram into it. I will also probably go with some higher CFM fans on my radiator. My specs are on the forum and some pics in the gallery but like you said, Mr A is the man when it comes to doing it up right.

PS In winter, when the house is cool, I can't keep my dog from laying next to the case to stay warm LOL.

Instead of the rod, I installed another rivet in the carriage and it worked out great.

My XPSC cover came off too so I have to find something to put it back on...

Same happened with one of mine. I think it was due to a leak I had when one of my acrylic T-Blocks cracked. I just used some clear Silicone which you can get in little tubes from Lowes or Home Depot for $3-4. It worked great and everything is staying in place now.

I also replaced the two acrylic T-Block with some metal BitsPower ones. I wish I would have gone with the metal ones from the beginning, but at the time I thought the acrylic ones would look "cool" with the colored coolant running through them.

Thanks for a great guide! I have no experience with dremel or rivet tools, so I did this in another way. You won't be able to mount the cage back again as easily if you should ever want that, and it was a bit PITA, but it went quick and well.

Tool list: Screwdriver, drill, cable cutting pliers (see pic)

Removed the two police baton shaped plastic thingies with a screwdriver

Used a drill to remove the bottom four of the six mentioned rivets on the front of the case (I did not remove the two at the top that you removed - NOTE, that is the two at the bottom of the OP's first pic, since the case is upside down)

Used standard cable-cutting pliers (see pic) to seriously screw up the two hard-to-reach rivets up on the inside of the cage (the rivet heads/bottoms/whatever were removed, something remained that I could not remove)

Used said pliers to bend and cut off the two taps at the bottom and two at the top (for both left and right) holding the cage sides in place. Real PITA when doing the two on the top front (inside of the cage), recommend removing one side of the cage completely first (next step) to get better access to the other.

The things you used your cable cutting pliers for will probably not be completely gone, mine weren't, so I grabbed one side at a time and bended back and forth until it came loose.

That's it, done! No dremel, no rivet tools needed, HDD cage mounts screwed up, band-aid on finger. If you know you won't remount the cage later anyway, then no problem.